Online score decreasing

Each satellite audit your node independently, if your node did not answer on audit request, your online score for this satellite is decreasing. When it started to answer - it will slowly recover, but to fully recover your node should be online (answers on audits) for the next 30 days.
Each downtime requires the next 30 days being online to fully recover.

You can use these scripts to figure out when your node was not available:

Then you can check your network, firewall and router on these dates to figure out, why your node was not available for audits.
It could be also your antivirus/firewall/ISP blocking requests from/to the specific satellite.